Multiple plug



May 12, 1925. 1,537,081

F. H. GRAHAM MULTIPLE PLUG Filed Dec. 15, 1925 p Affjz Patented Ma 12, 1925.

UNITED STATES PATENT OFFICE.

FRANK H. GRAHAM, OF YORK, N. Y., ASSIGNOR T0 WESTERN ELECTRIC COM- PANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW' YORK.

MULTIPLE I'LUG.

Application filed December 15, 1923. Serial No. 680,786.

To (all whom it may concern:

Be it known that I, FRANK H. GRAHAM, a citizen of the United States of America, residing at New York, in the county of New York, State of New York, have invented certain new and useful Improvements in Multiple Plugs, of which the following is a full, clear, concise, and exact description.

This invention relates to a portable mul tiple plug for .use in conjunction with a standard terminal strip for instantaneously converting a circuit from one character to another without soldering or unsoldering connections.

It is the object of the invention to pro- .vide .simple means for easily and quickly converting a telephone circuit from one character to another.

It is more specifically-the object of the invention to provide a portable multiple plug arranged for use in conjunction with the terminals of a standard terminal strip;

Referring to the drawings, Fig. 1 is a front elevation of a portable multiple plug embodying the invention and adapted to function with a standard terminalstrip. Fig.2 is a sectional view of the plug taken on line 22 of Fig.1 showing the manner in which the contact bearing members are pivoted in the frame of the plug for restricted rotational movement. Fig. 3 is an end view of the portable plug engaged with a standard terminal strip. Fig. 4 is a front viewofsFig. 3 showing the relation between the spring contactsand the front terminals of the rows of terminal punchings when the portable .plugxis in engagement with the terminal strip. "Fig. 5 represents in schematic form the manner inwhich the plug may beemployed for the conversion of circuits.

In general, the plugcomprise's a frame having two parallel bars 2 and of any suitable insulating material held in spaced relation by tubular members 5 also of insulating material and clamped together by bolts 6 entendingthrough the bars 2 and 3 and through the tubular members 5. Each end of the'bar 2 is formed with a finger grip L7 to enable the plug to be readily withdrawn from the strip 1.

Spaced at regular intervals in the bars 2 and 3 are openings 9, the openings in the twobars being disposed opposite each other and with their aXesin' alignment. In conjunction with each opening the bars are also provided on their adjacent faces with transversely extending notches 8.

Pivotally mounted in the aligned openings 9 of the bars 2 and 3 are contact hearing members at of insulating material. Each member a is provided at either end with a tongue as forming a pivot for engagement in an opening 9. lVhen the tongue 48 of a member -l is seated in an opening 9, the shoulders T formed on either side of the tongue 48 engage the sides of the corresponding notch 8, and since the width of the notch is slightly greater than the thickness of the member 4, the member 4 is permitted a slight rotational movement.

Mounted at regular intervals on each member are pairs of tapered contact springs 22 26, 2327, Qt-QS and 2529, the springs of each pair being disposed at opposite sides of the member at and attached thereto by rivets 31. The springs of each pair are thus electrically connected to gether. The free end of each spring is formed with teeth shown at 42 whereby a good electrical contact is insured between the edge of the spring and a terminal of the terminal strip 1 when the plug is positioned in engagement with the terminals of the terminal strip.

The pairs of spring contacts are so positioned on each contact bearing member 4 that when the plug engages with the terminal strip, each pair of contacts engages a corresponding pair of terminals located on adjacent rows of terminals as shown in Fig. 41-.

lVhen a manual telephone exchange operatcd on a call wire basis is installed and. which it is thought may later have to be converted .to operate on a call indicator basis, call wire circuits and apparatus are installed for initial use and call indicator equipment and wiring is provided for use when the exchange is to be operated on a call indicator basis. Each trunk, such as or 51, terminating in a jack before an operator has its apparatus which may be used when the trunk is operated either on a call wire or call indicator basis connected to the rear terminals of a row of terminal punchings as shown in Fig. 5. The leads from the call wire circuit apparatus indi catcd' at 40 are connected to the rear terminals oi? the adjacent row of terminal,

tioned between vertical rows of terminal punchings in the rear tern'iinals of which termimite the trunk circuits and the call wire circuits, respectively. By pressing the plug downward until/the bottom side of bar is resting upon the upper side of base 1 of the terminal strip, the spring contacts 22, 23,2 1, 25, 26, 27, 28 and 29 of each 'con tact member "fare forcibly pressed against the terminals 10, 11, 12, 13, 1 1, 15., 16 and 17 respectively, so that a firm contact is made thereby connecting the trunk circuit and call wire'circuit apparatus through the front terminals and the spring contacts.

The contact bearing members 4, shown in Fig. 1 being mounted rotatably in the notches S of the parallel bars, permits each contact bearing member 4 of the plug to adjust itself to variations in the alignment of the rows of terminals within the limits in which the Contact bearing members may be rotated.

.Vhen the time arrives for converting the trunk circuit from call wire trunk circuit to call indicator trunk circuit, conversion is accomplished easilyand quickly by the instailer pressing a thumb on each linger grip and exerting a slight upward pressure thereon disengaging the spring contacts "from the tern'iinals and permitting the plug to be removed laterally from the strip 1 Disengaging the contacts disconnects the call wire circuit apparatus from the trunk circuit. The installer ii'nmediately inserts the portable plug over the rows of terminals of the terminal strip so that the contacts 2:2, 23, 2 1', 25 and 26, 2'7, 28 and 29 of each contact bearing member 1 engage respectively with the front terminals of punchings'l'st, 15, 16, 17 and 18, 19, 20 and 210i adjacent rowsof punchings, thereby connecting the trunk circuit to the-call indicator circuit apparatus which is connected to the rear terminals resl'iectivelyof punchings 141, 15, 16, 17, and 18, 19, 20, and 21.

' It is to be noted that although the invention has: been described in connection with the conversion of a call wire trunk circuit to a call'indicator trunk circuit the invention is not to be considered limited for use with any particular kind of circuits, since it is obvious that this portable plug arranged to functionwith a: standard telephone system terminal strip may be used for converting any kind of circuits from one character 2. In a multiple plug, a frame comprising bars parallelly disposed-and spacingmembers, contact supporting members extending between said bars and pivotally supported therein, means "for restricting the pivotal movement of said supporting members, and

spring contact-s carried by said supporting members.

6') I o. In a multiple plug, a rrame comprismg bars parallelly disposed and spacing members, said bars having pivot openings therein, the openings in said bars respectively being oppositely disposed with" their axes in alignment, contact supporting members extending between said bars and'pivotally supported in said openings, means for restricting the pivotal movement of said supporting members, and spring contacts carried by said supporting members.

1. In a multiple plug, a frame comprising bars parallelly disposed and spacing members,-said bars having transversely extending notches and associated pivot openings in the adjacent faces thereof, the'notches and openings in said bars respectively be ing oppositely disposed with the axes of said openings in alignment, contact supporting members extending between said bars and pivotally supported in said openings, the ends of said supporting members being so disposed in said notches that the pivotal movement of said members is restricted by the walls of said notches, and spring contacts carried by said supporting members.

5. In a multiple plug, a frame comprising bars parallelly disposed and spacing members, contact supporting members extending between said barsand supported therein, and pairs of contact springs carried by said supporting members, the contact springs of each pair being disposed on opposite sides of its supporting member and electrically connected therethrough.

6. In a multipleplug, a'frame comprising bars parallelly disposed and. spacing members, contact supporting members Of insulating material extending between said bars and supported therein, and a plurality of'pa-irs of contact springs carried by each of said supporting members, the contact springs of each pair being disposed on opposite sides of its supporting member and elec tri'cally' connected therethrough.

7 In a multiple plug, a frame comprising bars parallelly disposed and spacing,

members, contact supporting members of insulating material extending between said bars and supported therein, and pairs of contact springs carried by said supporting members, the contact springs of each pair being disposed on opposite sides of its sup,- porting member and having their free contacting ends serrated.

8. In a switching device, the combination of a terminal strip having a plurality of rows of terminals arranged insets, with a multiple plug comprising a frame, contact supporting members mounted therein arranged for insertion respectively between the rows of terminals of said sets, and pairs of contacts carried by said members, the contacts of each pair being disposed on opposite sides of its supporting member and electrically connected together, whereby oppositely disposed terminals of adjacent rows may be connected.

9. I11 a switching device, the combination of a terminal strip having a plurality of rows of terminals arranged in sets of three, with a multiple plug comprising a frame, contact supporting members mounted there in and pairs of contacts carried by said members, the contacts of each pair being disposed on opposite sides of its supporting member and electrically connected together, said plug being arranged to engage with said terminal strip so that said contacts engage and connect the corresponding terminals of the middle row of each set and of either row adjacentthereto.

10. In combination with a terminal strip having a plurality of rows of terminals, a portable plug comprising a plurality of contact bearing members, and a plurality of pairs of spring contacts on each of said members, said plug making contact between, corresponding terminals of certain adjacent rows of terminals in one position on said strip and in another position connecting corresponding terminals of other adjacent rows of terminals.

11. In a switching device, a plurality of groups of rows of terminals conveniently located in a terminal strip, each group comprising three rows of terminals, one row of terminals of each group being connected to circuits, a second row of terminals in each group adjacent to said one row being connected to one kind of apparatus, a third row of terminals in each group also adjacent to said one row of terminals being connected to a different kind of apparatus, said circuits being possessed of one character when the corresponding terminals of said one row of terminals and said second row of terminals of each group of rows of terminals are connected, said circuits being possessed of a different character when the corresponding terminals of said one row of terminals and said third row of terminals of each group of terminals are connected, a portable plug arranged to be inserted between said rows of terminals to connect the corresponding terminals of adjacent rows of terminals so as to enable the operator to convert said circuits from one character to a different character and vicev versa, by causing said portable plug to either connect the corresponding terminals of said one row of terminals and said second row of terminals or to connect the corresponding terminals of said one row and said third row of terminals.

In witness whereof, I hereunto subscribe my name this 1th day of December A. 1)., 1923.

FRANK H. GRAHAM. 

